Inverse magnetic catalysis in dense holographic matter

Abstract

We study the chiral phase transition in a magnetic field at finite temperature and chemical potential within the Sakai-Sugimoto model, a holographic top-down approach to (large-N_c) QCD. We consider the limit of a small separation of the flavor D8-branes, which corresponds to a dual field theory comparable to a Nambu-Jona Lasinio (NJL) model. Mapping out the surface of the chiral phase transition in the parameter space of magnetic field strength, quark chemical potential, and temperature, we find that for small temperatures the addition of a magnetic field decreases the critical chemical potential for chiral symmetry restoration - in contrast to the case of vanishing chemical potential where, in accordance with the familiar phenomenon of magnetic catalysis, the magnetic field favors the chirally broken phase. This "inverse magnetic catalysis" (IMC) appears to be associated with a previously found magnetic phase transition within the chirally symmetric phase that shows an intriguing similarity to a transition into the lowest Landau level. We estimate IMC to persist up to 10^{19} G at low temperatures.Comment: 42 pages, 11 figures, v3: extended discussion; new appendix D; references added; version to appear in JHE

Chiral and deconfinement transitions in a magnetic background using the functional renormalization group with the Polyakov loop

“…For large values of the chemical potential µ, the critical temperature is a decreasing function of the magnetic field. This is inverse catalysis [54,55]. We also find that the transition temperature is increased signficantly for all values of µ with the addition of the Polyakov loop.…”

Anisotropy in the equation of state of magnetized quark matter

“…Some of the most important changes concern the size and location of the first-order chiral transition region since the results show that a strong magnetic field favors this type of transition. At the same time, at low temperatures, the value of the coexistence chemical potential decreases as B increases in accordance with the inverse magnetic catalysis (ICM) phenomenon [3].The low-T and high-μ region where a first-order-type transition is expected to occur is currently unavailable to lattice QCD evaluations (LQCD). However, the region high-T and low-μ has already been exploited using LQCD simulations which indicate, in accordance with most model predictions, that the crossover observed at B = 0 persists when B = 0 [4][5][6][7].…”

(Inverse) magnetic catalysis in non-relativistic Bose-Einstein condensation

“…The recent lattice calculations [7], however, provide surprising results that the chiral pseudo-critical temperature significantly decreases for increasing magnetic field. On the other hand, the chiral condensate increase with increasing magnetic field at low temperature consistent with magnetic catalysis while it turns out to a monotonously decreasing at high temperature [8], which is in apparent conflict with magnetic catalysis and termed as inverse magnetic catalysis evoking an extensive studies [9][10][11][12][13][14][15][16].…”